Improvement in hand-pieces of dental engines



B. S BROWN. Hand-Pieces of Dental-Engines.'

No. 213,167. Patented Mar. 11,1879.

W-/T/VESSES.

NA FET-ERS. PHOTO-UTHOGRAFHER. WASHNGTON. D. C.

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BENONI S. BROWN, OF NEV YORK, N. Y.

Specilication forming part of Letters Patent No. 213,167, dated Marchl1, 1879; application filed December 20, 1878.

To all whom it may concern Beit known that I, BnNoNr S. BROWN, of thecity, county, and State of New York, have invented certain new anduseful Improvements in the Hand-Pieces of Dental Engines; and I dohereby declare the following to be such a full, clear, concise, andexact description as will enable any one skilled in the art or scienceto which it appertains or with which it is most nearly connected to makeand use the same, reference being had to the accompanying drawings.making part of this specification, and to the several figures andletters of reference marked thereon, as hereinafter described.

The object of these improvements is to more eiiectually and permanentlysecure the operating-tool in the hand-piece, to increase the durabilityand general lirrnness of the handpiece itself, and to facilitate itsrepair.

The dental hand-piece is an instrument well known to those skilled inthe art and science of dentistry, and to those skilled in the art ofmanufacturing dental instruments. I will not, therefore, in describingthese improvements, give a full detail description of a dentalhandpiece, but confine myself to a description of the parts, and theirapplication, comprising my invention.

By Figure l of the drawings is shown an eX- ternal view of thehand-piece ready for use. Fig. 2 illustrates a longitudinal verticalsection through the same 5 and Figs. 3, 4, and 5 show detail parts, tobe hereinafter referred to and explained.

In Figs. l and 2, A is the operating-tool. By B, Fig. 3, is shown thetool-holder that carries the tool. By G and H of Fig. 5 are shown thejournals that support and carry the tool-holder; and by C of Fig. 5 isshown a connecting-tube, to which the journals are united or held inposition.

To permanently' hold the tool A rmly in the holder that carries it, andto permanently hold the spindle snugly in its journals, and keep thejoints of the case tight and irm, are the principal points of theinvention.

The spindle is a composition one, and consists of the tool-holder B, andthe journals G and H, held apart by a tube, c. The end of thetool-holder is slotted and enlarged, as shown by ls and o, and in it theshank of the tool is inserted in the ordinary way. Upon the opposite endof the spindle, or near its end, a collar, j, is made, and around thespindle, under this collar, a helical spring, i, is wound. The journalsH and G are united to the connectingtube c by soft solder. It is notnecessary that these parts be soldered together 5 but I prefer to havethem so. The tube with its journals are now slipped over the split endof the tool holder or clutch, and shoved down against the spring t'. Indoing so the jaws 0f the clutch k are contracted or forced to thecenter, and are kept so until, by forcing the tube-journals down uponthe spring, the end of the tool-holder protrudes beyond the end of thejournal G or chuck, by which the jaws of the clutch are released and theshank of the tool is inserted. The springt then with a constant forcepresses the end of the journal G or chuck against and upon theenlargement or cone on the jaws of the tool-holder, and maintains a'constant and uniform grasp upon the shank of the tool, holdin gitfirmly, notwithstanding the wear and reduction of the parts in contact,as long as the spring has energy enough to force the tubo or chuck uponthe cone of the clutch.

The lowerlend of the j ournal-box (the chuck) should, of course, belitted to the shape of the enlargement or cone on the clutch, and theparts in contact should be made of steel, tem-' pered hard and polishedsmoothly.

I have shown how the tool is griped and permanently held in the jaws' ofthe clutch by the constant force of the spring drawing it within theembrace of the chuck.

The manner in which the spring is made to release the shank of the toolis as follows: The case of the instrument consists of four parts, L IPQ. The parts I and P are united by means of a tubular screw-nipple orjournal-box, E, upon which a left-hand thread is cut, and in which thejournal H of the spindle is carried, the lower end of the nipple forminga shoulder, against which the thrust-collar ofthe journal rides. Thepart Q of the case is made with a shank, S, that is snugly fitted intothe part P, and yet loose enough to admit of being turned by the hand.In this shank a screw-pin, I, is

fitted and arranged in a cam-slot, m, cut in the part I), so that uponturning the pa-rt Q the length of the cam-slot it will advance in or outof'the part P a distance equal to the pitch ofthe cam. Ihe shank of thepart Q is also made to slip over and embrace the collar j on the end ofthe tool-holder B, upon which a shoulder, H, of the shank rides. Now, ifthe part Q be turned to the left to bring` the pin lin the left endofthe cam-slot, the spindle will be forced forward by the shoulder Xupon the collar 7' of the spindle, and the shank ofthe toolA will bereleased but by turning the part Q to the right, so as to bring the pinl in the opposite end of the camslot, the spring will force back thespindle, and draw the clutch in the end of journal G or chuck, and closethe jaws ofthe clutch on the shank of the tool A.

Toiusure the effectual opera-tion ofthe parts, as above described, thecollars a and b on the journals G H should be snugly held between theend of the nipple E and a corresponding shoulder in the lower end of thecase I.

To avoid all lost motion or slack adjustment at these points is theobject of the screw-nipple or journal-box, by which the wea-r betweenthe shoulders and the collars can be readily compensated for, and thelost motion taken up by merely screwing down the nipple or screwjournalbox far enough to take up the slack, a hole, f, being made in the nippleto receive the end of a rod, to screw it up or down, as may be required.

The screw-thread on the nipple is cut to the left, that its position maynot be affected by the rotation of the spindle in it.

To press back the part Q of the case and keep it from too readilyturning upon the campin l, or feeling loose in the hand, a spring, o, isinserted under the end of its shank, and over the springt upon the endof the nipple, by which all misplacement or undue looseness is avoided.

Having thus described the nature and extent of my invention, I claim anddesire to secure by Letters Patent- 1. A dental hand-piece fitted with asplit tool-holder, B, combined with a spring', 1T, arranged toconstantly draw or force the toolclu'tch within the embrace of thechuck, by which the tool is firmly griped and held 1n position,

2. A dental hand-piece fitted with a split tool-holder, B, combined witha cam, m, cutin the case and fitted with a pin, as described, arrangedto act on the tool-holder and force its split end out of the embrace ofthe chuck and release the tool.

3. In a dental hand-piece, the tubular screwnipple E, in combinationwith the upper part of the case and the upper journal of the spindle, bywhich the lost motion of the spindle endwise can be taken up by theadjustment of the journal-box, in which it is supported.

4. A dental hand-piece in which the two journals that carry thespindleare made separate and distinct, and are held in position endwise by anintervening tube, so that old boxes can be readily replaced by new ones.

BENONI S. BROWN.

Witnesses:

WILLIAM H. BROADNAX, AMos BROADNAX.

